[Defense / Survival] Hero Siege

[Lilith]

Hi Everyone ; )

I'm looking for interested people who would like to work together and create wonderful map. Our target is to make as good map as DOTA. [I mean style of gameplay].

I'm making a bigger project. It's a standard Hero Defense. You're picking a hero and defending Altar on the center of the map.
Items are in 6 categories:
Level 1 Items
Level 2 Items
Level 3 Items
Level 4 Items
Level 5 Items
Level 6 Legendary Items

There is also Tome Shop and Potion Store

Also, you get curier who can bring your hero items.
You can challenge bosses and get various kinds of rwards.
100 000 gold = 1 lumber [there is a Gold Converter]

But my Main Question is:
How to design gamplay to be very attractive to players?

I thought about 1 vs 5 or 2 vs 5. 5 players are defending and 1 or 2 players are besieging base, commanding all the creeps and bosses.

Any kind of help will be very useful, any idea. ; D
Thanks for attention


PS. This is my first thread on this amazing forum filled with lots of great staff.
If there are any misspellings I'm sorry. English is my second language.